Oil pressure fluctuations normal as mentioned by others. If you continue to lose coolant, it's going somewhere and if it's not leaking it (INSPECTION) then it's burning it. A pressure test or a leakdown test can give you some real clues there...Sounds like the visual inspection of the oil would be enough for me to do some hardcore testing to determine root cause. Good Luck!
99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche
Without "data", all you have is an opinion!